A general library apparatus includes a magazine which is equipped with a plurality of magazine cells, a read/write device which reads data from a storage medium stored in the magazine cell and writes data in the storage medium, and an access device which carries the storage medium between the magazine and the read/write device. The magazine cell is arranged so as to store a plurality of storage media.
Then, the magazine is withdrawn from the library apparatus and one magazine cell is discharged from this magazine. Furthermore, the storage medium is withdrawn from the discharged magazine cell and afterward, the storage medium is stored again.
When the library apparatus is activated or the storage medium is stored, etc, the library apparatus carries out an inventory process in order to check the storage medium, which is stored in each magazine cell, and arrangement of the storage medium.
However, there is a problem that it takes a long time for the library apparatus, in which a large number of storage media are mounted densely, to carry out the inventory process.
Then, Japanese Patent Application Laid-Open No. 1998-106112 proposes an optical disc changer including a storage medium discharger which can make only a small number of magazine cells discharged, and enabling to store the storage medium only in the discharged magazine cell, etc.
Since the storage medium is withdrawn only from the specific magazine cell (referred to as a movable cell) and stored in the specific movable cell as mentioned above, it is possible to limit an object of the inventory process to the storage medium which is mounted in the movable cell. Accordingly, it is possible to reduce a time required for the inventory process.
Moreover, since the storage medium is withdrawn only from the movable cell and ill inserted only into the movable cell, an operator can withdraw and insert the storage medium on the basis of an intuitive judgment. That is, it becomes easy to withdraw and insert the storage medium.
By the way, it is necessary to mount the storage medium in a right direction, when mounting the storage medium in the magazine cell. However, the storage medium may be mounted in a wrong direction in some cases due to a human error, since the storage medium is mounted by the operator. Accordingly, it is necessary to arrange a mechanism to prevent the wrong insertion due to the human error (hereinafter, described as wrong insertion preventing mechanism).
However, the optical disc changer according to Japanese Patent Application Laid-Open No. 1998-106112 is not equipped with the wrong insertion preventing mechanism mentioned above. While it is possible to add the wrong insertion preventing mechanism of course, number of the storage media which can be stored in the library apparatus may become small in some cases due to the addition of the wrong insertion preventing mechanism. The reason is that there is a regulation on sizes in height and width of the library apparatus. When the library apparatus is mounted on a general rack, a size in depth of the library apparatus is restricted substantially by a size in depth of the rack.
In order to add the wrong insertion preventing mechanism under the condition of the regulation and the restriction, number of the storage media to be stored must be reduced so that a space for storing the wrong insertion preventing mechanism may be secured.